Self-supporting liquid bag



April 8, 1969 E. KUGL ER 3,437,258

SELF-SUPPORTING LIQUID BAG Filed July 20, 1967 INVENTOR. ham/s4 4 mrm United States Patent Office 3,437,258 Patented Apr. 8, 1969 3,437,258 SELF-SUPPORTING LIQUID BAG Emanuel Kugler, 124 Richmond Place,

Lawrence, N.Y. 11559 Filed July 20, 1967, Ser. No. 654,815 Int. Cl. B65d 31/08, 33/02 U.S. Cl. 229-58 2 Claims ABSTRACT OF THE DISCLOSURE The present invention relates generally to plastic bags, and more particularly to an improved plastic bag capable of standing when filled with liquid.

Plastic bags are a popular product package for many reasons, including the reason that this material readily lends itself to economical mass production when being converted into bags. Perhaps the only serious -disadvan tage of plastic is that it lacks suflicient rigidity or body so that the resulting bag can stand and, for example, thus readily be used in shelf displays and the like.

Broadly, it is an object of the present invention to provide an improved plastic bag which, when filled with liquid, can easily be made to stand and in this and other respects overcomes the foregoing and other shortcomings of prior art plastic bags. Specifically, it is an object to provide a plastic bag having an improved bottom gusset construction which provides the bag with a standing base and which can readily be embodied in the bag without adversely affecting either the rate or the costs of pro duction.

A liquid-containing plastic bag demonstrating objects and advantages of the present invention is, in part, of conventional construction having the usual sealed together front and rear walls and a bottom gusset. The departure from prior art resides in the formation of triangular shaped enclosures in each of the two halves of the bottom gusset, these enclosures, when filled with liquid, being movable in opposite directions away from each other to thereby unfold the bottom gusset into a standing base for the bag.

The above brief description, as well as further objects, features and advantages of the present invention, will be more fully appreciated by reference to the following detailed description of a presently preferred, but nonetheless illustrative embodiment in accordance with the present invention, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a plastic bag demonstrating objects and features of the present invention;

FIG. 2 is a partial end perspective view of the bag, looking in the direction of the bottom gusset construction of the bag;

FIG. 3 is an elevational view, in section taken on line 33 of FIG. 1, illustrating details of the bag bottom gusset construction;

FIG. 4 is a partial elevational view, on enlarged scale, in section taken on line 44 of FIG. 1, illustrating further details of the bottom gusset construction;

FIG. 5 is a front elevational view of the bag filled with liquid and illustrated in its vertical self-supporting standing position, portions of the bag being broken away to illustrate further details of the bottom gusset construction;

FIG. 6 is an end elevational'view, in section taken on line 66 of FIG. 5, illustrating the manner in which the bottom gusset unfolds to provide lateral support for the bag; and

FIG. 7 is a bottom view of the bag similar to FIG. 2, but of the bag filled with liquid.

Reference is now made to the drawings wherein there is illustrated a plastic bag 10 demonstrating objects and advantages of the present invention. The bag 10 is preferably fabricated of a heat scalable material such as polyethylene which, in a known manner, readily lends itself to the economical mass production of the bags on conventional bag-making apparatus. It is equally well known that this material is flexible and ordinarily lacks sufiicient rigidity or strength to enable the bag 10 to readily assume a self-supporting standing position. The bag 10 hereof nevertheless has an operative standing position when filled with a liquid L, as illustrated in FIG. 4. The liquid L may be any one of many possible fluid commodities, such as milk, soda, etc.,'the choice of which is not intended as a limitation on the scope and breadth of the present invention. The invention resides essentially in the bottom gusset construction, generally designated 12, which functions in the manner as subsequently described in detail herein to provide an open base, as best illustrated in FIG. 7, which is effective in supporting the bag 10 in a standing position.

More particularly, the bag 10 includes the usual front wall 14 and rear wall 16 joined to each other along side seams or welds 18 and 20. In accordance with conventional practice, the bag 10 also includes as part of the bottom gusset 12 a bottom' wall 12a tucked inwardly of the bag and having a fold line 12b which delineates the wall 12a into two equal folds or wall sections, herein specifically designated 12c and 12d in FIG. 2. Thus, as best illustrated in FIG. 2, the bottom wall 12a is divided into two sections 12c, 12d, each of which is integrally connected along an edge to the bag front wall 14 and 16, respectively. The gusset sections 12c and 12d are sealed to each other by the side welds 18, 20 but, along their length therebetween, are unconnected to each other and thus free to be moved in opposite directions from each other, as denoted by the double headed arrow A.

In accordance with the present invention, the foregoing unfolding movement A of the gusset folds 12c and 21d occurs automatically upon the introduction of liquid L into the interior of the bag 10 through the upper opening 22 thereof. To this end, each gusset fold 12c, 12d is respectively joined to the bag walls 14 and 16 by a converging set of heat seals 24 and 26. In the preferred embodiment illustrated herein, each heat seal line 24, 26 of each set originates at the juncture of the fold line 12!) with the side welds 18 and 20 and angles therefrom so as to converge to within close proximity of each other at the intersection of the heat seals with the bottom edges 12a and 12 of the bag 10. It should be noted that the heat seal lines 24, 26 join only the confronting lower portions of the front and rear walls 14 and 16 to the gusset wall sections and 12d but do not join the gusset wall sections to each other. To achieve this during manufacture of the bags 10 use is advantageously made of a heat seal inhibiting coating on the confronting surfaces of the bottom wall 12a such that these surfaces do not fuse to each other when the heat seals 24 and 26 are applied to the plastic material. This heat seal inhibiting coating, which may be any commercially available polyamide-base ink, is, of course, not applied to the areas of the bottom wall 12a which are joined in the side welds 18 and 20.

As a result of the converging set of heat seals 24 and 26, when a liquid L is introduced into the interior of the bag 10 it flows into the funnel-like or triangular shaped enclosures which are delineated by these heat seals. This, in turn, has the effect of localizing the pressure or weight of the liquid L at the point of convergence of the heat seal lines 24, 26 with the bag edges 12c and 12 and, yielding to this localized pressure, the gusset 12 unfolds in the direction A until the unfolded condition of FIG. 7 is achieved. In this unfolded condition of the bottom gusset 12 there is a suflicient area bounded by the spread-apart bag edges 12e, 12 to provide a stable base for a self-supporting standing position for the bag 10.

In a preferred embodiment of the bag 10 as illustrated herein an additional converging set of heat seals 28 and 30 are applied to the bottom gusset 12 in the triangular segments which are delineated by the previously noted heat seal lines 24, 26, the lower bag edges 12e and 121, and the side welds 18 and 20. This set of heat seals 28 and 30 is optional in that it is not necessary to effect a weight distribution of the liquid L causing unfolding of the gusset 12 but is preferred since it adds to the rigidity of the triangular gusset segments and to the bag bottom edges 21c and 12 on which the bag stands. Like the heat seals 24 and 26, the heat seals 28 and 30 are applied using a heat seal inhibiting coating so as to fuse the gusset folds 12c and 12d to the bottom portions of the front walls 14 and 16 but without fusing the gusset folds 12c and 12d to each other.

From the foregoing it should be readily appreciated that the bag 10 hereof has an unfolding bottom gusset construction 12 which effectively and automatically provides the bag with a self-supporting standing position. This, in an obvious manner, greatly increases the value of the bag as a package for fluid commodities since it facilitates shelf display of the package and, in the case of milk or other drinkable fluids, also facilitates use by enabling the user to stand the bag 10 during intervals between drinking. Moreover, when used as a container for drinkable fluids, as an optional feature the bag can also include a straw which would be readily accessible at one end to the user and at its other end in communication with the bottom interior of the bag. However, since straws have heretofore been incorporated in prior art bag constructions an exemplary description has not been repeated herein.

A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.

What is claimed is:

1. A plastic bag having an operative self-supporting standing position when filled comprising a front wall, a rear wall and a bottom wall formed of a single sheet of continuous, uniform thickness, flexible, heat scalable film material, side welds attaching said front and rear walls to each other along opposite side edges to form a bag construction bounding an internal volume, said bottom wall forming a gusset construction at the bottom of said bag between the bottom edges of said front and rear walls, said bottom Wall being folded inwardly therebetween along a fold line dividing said bottom wall into a pair of gusset wall sections, said gusset wall sections being attached at opposite edges to each other by said side welds, and a pair of converging heat seals joining each said gusset wall section to the respective confronting portion of said front and said rear wall, each said pair of heat seals originating at locations in the side edges of said bag adjacent said gusset fold line and oriented at an inclined angle therefrom so as to converge toward each other in the direction of the bottom edge of said bag and terminating adjacent each other in said bottom edge to thereby delineate a triangular shaped enclosure between each said gusset wall section and said bag front and rear walls, the medial portions of said triangular shaped enclosures being movable in opposite directions away from each other when said bag is filled to thereby cause unfolding of said bottom gusset construction into a standing base for the bag.

2. A plastic bag having an operative self-supporting standing position when filled comprising a front wall, a rear wall and a bottom wall formed of a single sheet of continuous, uniform thickness, flexible, heat scalable film material, attached to each other along opposite side edges to form a bag construction bounding an internal volume, said bottom wall forming a gusset construction at the bottom of said bag between the bottom edges of said front and rear walls, said bottom wall being folded inwardly therebetween along a fold line dividing said bottom wall into a pair of gusset wall sections, a first inner pair of converging heat seals joining each said gusset wall section to the respective confronting portion of said front and said rear wall, each said pair of heat seals originating at locations in the side edges of said bag adjacent said gusset fold line and oriented at an inclined angle therefrom so as to converge toward each other in the direction of the bottom edge of said bag and terminating adjacent each other in said bottom edge to thereby delineate a triangular shaped enclosure between each said gusset wall section and said bag front and rear walls, said triangular shaped enclosures being movable in opposite directions away from each other when filled to thereby cause unfolding of said bottom gusset construction into a standing base for the bag, and a second outer pair of heat seals oriented generally parallel to said first inner pair of converging heat seals effective to seal said gusset wall sections to said front and rear walls and thereby increase the rigidity of the bottom edges of said bag.

References Cited UNITED STATES PATENTS 3,380,646 4/1968 Doyen et al. 22957 D. 173,933 2/1955 Cargill et al.

2,265,075 12/1941 Kneutter. 2,821,337 1/1958 Morgan 22957 3,136,475 6/1964 Geimer 22957 3,143,277 8/1964 La Fleur 22957 DAVID M. BOCKENEK, Primary Examiner.

US. Cl. X.R. 22953, 57 

